Leioclema multiacanthoporum

Ernst, Andrej, Fernández, Luis Pedro, Fernández-Martínez, Esperanza & Vera, Carmen, 2012, Description of a bryozoan fauna from mud mounds of the Lebanza Formation (Lower Devonian) in the Arauz area (Pisuerga-Carrión Province, Cantabrian Zone, NW Spain), Geodiversitas 34 (4), pp. 693-738 : 712

Leioclema multiacanthoporum (Astrova in Astrova & Yaroshinskaya, 1968) ( Fig. 12 A-F; Appendix)

Lioclema multiacanthoporum Astrova in Astrova & Yaroshinskaya, 1968: 54, pl. 2, fig. 3. — Kopajevich 1984: 62, pl. 17, fig. 2.

MATERIAL. — SMF 21.221- SMF 21.226.

DESCRIPTION

Branched colonies, branches 1.8-3.1 mm in diameter, with 0.57-1.09 mm wide exozones and 0.66-0.92 mm wide endozones. Autozooecia budding from a thin epitheca, briefly oriented parallel to the substrate, then bending sharply and intersecting the colony surface at right angles. Autozooecial apertures rounded-polygonal to petaloid due to indenting acanthostyles. Autozooecial diaphragms rare to absent, thin, straight or slightly deflected proximally. Mesozooecia common, locally abundant, 2-5 surrounding each aperture, polygonal in cross section, slightly beaded, containing planar diaphragms. Acanthostyles moderately large, abundant, 4-9 surrounding each aperture, originating from the base of exozone, often indenting autozooecia, having distinct calcite cores and dark laminated sheaths. Walls granular, 0.010 -0.015 mm thick in endozones; distinctly laminated, 0.025 -0.065 mm thick in the exozone. Maculae not observed.

COMPARISON

Leioclema multiacanthoporum is similar to L.elegans Ernst, 2008 from the Lower Devonian of Prague Basin and NW-Spain (Ernst 2011), but differs from the latter in having more abundant acanthostyles (4-9 vs 3-6 in L. elegans ) and smaller distances between aperture centres (0.20 mm vs 0.26 mm in L. elegans on average).

The Spanish material described here is more similar to the original description of Astrova (Astrova & Yaroshinskaya 1968) than Mongolian material which differs in having thicker stems (5-10 mm vs 2-3 mm in material from Altai and Spain). Consequently, the Mongolian representatives of this species have a larger number of mesozooecia (4-9 vs 4-7 and 2-5 in Altai and Spanish material respectively).

Suborder AMPLEXOPORINA Astrova, 1965

Figures

FIG. 12. — A-F, Leioclema multiacanthoporum (Astrova in Astrova & Yaroshinskaya, 1968): A-C, branch oblique section showing autozooecia, mesozooecia and acanthostyles,SMF 21.225; D, branch transverse section, SMF 21.221; E, longitudinal section showing autozooecia and mesozooecia, SMF 21.222; F, tangential section showing autozooecial apertures, mesozooecia and acanthostyles, SMF 21.226; G-I, Eridotrypella validaeformis n. sp.: G, branch oblique section, paratype SMF 21.385; H, longitudinal section showing autozooecia with diaphragms, holotype SMF 21.227; I, tangential section showing autozooecial apertures and rare exilazooecia, holotype SMF 21.227. Scale bars: A-C, I, 1 mm; D, G, 2 mm; E, F, 0.2 mm; H, 0.5 mm.